1. Field of the Invention
The present invention relates to a liquid discharge head and a head cartridge used for a printer, a video printer, or the like, which serves as an output terminal of a copying machine, a facsimile equipment, a wordprocessor, a host computer, or the like. The invention also relates to a liquid discharge apparatus provided with such liquid discharge head, and a method for manufacturing liquid discharge heads. More particularly, the invention relates to a liquid discharge head which discharges ink or some other liquid for use of recording as flying droplets from its discharge ports (orifices) to record by allowing such liquid to adhere to a recording medium. The invention also relates to a head cartridge and a liquid discharge recording apparatus provided with such head, as well as a method for manufacturing liquid discharge heads.
2. Related Background Art
Conventionally, an ink jet recording apparatus, which performs recording, as a liquid discharge recording apparatus, by discharging ink from the orifices of the liquid discharge head, is known as an excellent recording apparatus in that it has lower noises, and higher recording speeds, among some other advantages. As to the ink jet recording methods for such ink jet recording apparatuses, there have been proposed many methods, and some of them have been implemented as products and already put on the market after some improvements, while some of them are still under study at present for the implementation of its practical use.
As an example of the liquid discharge head used for the ink jet recording apparatus, there is one which is schematically shown in FIG. 1 and FIG. 2. FIG. 1 is a cross-sectional view which shows a part of the liquid discharge head manufactured by the conventional art. FIG. 2 is an exploded perspective view which schematically shows the liquid discharge head represented in FIG. 1.
As shown in FIG. 1 and FIG. 2, the conventional liquid discharge head comprises an orifice plate 440 having a plurality of discharge ports (orifices) 441 for discharging ink; a ceiling plate 400 for the formation of plural liquid flow paths 401 communicated with each of the discharge ports 441; and an elemental substrate 100 having a plurality of electrothermal transducing devices (heaters) 101 on it for the generation of thermal energy to discharge ink from the discharge ports 441. Therefore, the head is formed by the ceiling plate 400, and the head substrate 200 which is provided with the plural electrothermal converting elements 101 and liquid flow paths 401. Then, the orifice plate 400 is directly bonded to the head substrate 200 by use of bonding agent.
On the orifice plate 440, fine discharge ports 441 are formed for ink discharges as described above. Each of the discharge ports 441 is an important constituent of a liquid discharge head upon which its performance depends greatly. Then, in order to stabilize the directions in which ink droplets are discharged from each of the discharge ports 441, it is known that the circumference of each discharge port 441 of the orifice plate 440 should desirably be provided with the liquid repellency (hereinafter referred to as ink repellency or an ink repellent layer to make the description simpler) at least on its outer surface side. Therefore, it has been practiced to form the ink repellent layer on the surface of the orifice plate for the provision of the ink repellency on the circumference of each discharge port.
However, the outer surface 440a of the orifice plate where the ink repellent layer is formed is rubbed by the cleaning blade for wiping, which is needed for the maintenance of ink discharge condition by the execution of the recovery process thereof. As a result, there may be a case where the ink repellent layer is scraped by the cleaning blade and worn out or damaged depending on the material of the ink repellent layer, the formation method thereof, the material of the blade, or the like. Then, it is becomes difficult to maintain the ink repellency of the kind in good condition for a long time in some cases.
Therefore, attention has been given to this worn-out problem of the ink repellent layer, and for example, it has been proposed to disperse the ink repellent material in the material with which to form the orifice plate as disclosed in the specification of Japanese Patent Application Laid-Open No. 57-157765.
Nevertheless, when the material having ink repellency in it is used as the material of the orifice plate, there is encountered a new problem that in general, the higher the ink repellency contained in a material, the lower becomes the bonding power between the orifice plate and the head substrate. As a result, it has not been implemented as yet to provide a highly reliable liquid discharge head which is capable of maintaining the ink repellency of the orifice plate in good condition, while presenting the firm bonding between the orifice plate and the head substrate. This problem has been dealt with only by the improvement attempted to provide the ink repellent layer more effectively so far.
Under the circumstances, the inventors hereof have studies and acquired the knowledge that with the surface treatment given to the orifice plate at least on its bonding surface side, it becomes possible to bond the orifice plate with the head substrate in good condition even when adopting the fluororesin having an excellent ink repellency or the resin having the ink repellent material dispersed in it as the orifice plate material.
The present invention is designed with such new knowledge that the inventors hereof have acquired. It is an object of the invention to provide a liquid discharge head for which the bonding force is secured firmly between the head substrate, and the orifice plate having ink repellency on it to be made capable of maintaining a good ink repellency for a long time, and to provide a head cartridge using such head as well. It is also the object of the invention to provide a liquid discharge apparatus using such head, and a method for manufacturing ink jet heads.
In this respect, the orifice plate is a thin film sheet of approximately several tens of pm in some cases, depending on the modes to be adopted. Then, when resin or the like is used as the material of the orifice plate, the strength of the orifice plate becomes weaker to make its handling difficult. Also, the orifice plate is subjected to expansion or deformation due to heat if a high temperature treatment is given when the orifice plate is bonded to a head substrate. Particularly, since the thermal expansion coefficient is different depending on the material to be used, this phenomenon tends to exert influence on the bonding of the orifice plate and head substrate.
It is another object of the invention to provide a liquid discharge head whose orifice plate is capable of maintaining a good ink repellency for a long time even when a thin resin material having ink repellency or the like is used for the orifice plate which is bonded to the head substrate at a high temperature, and also, it is made possible to prevent the orifice plate from being expanded or deformed by the application of heat so as to bond the orifice plate assuredly to the head substrate. It is still another object of the invention to provide a head cartridge, a liquid discharge recording apparatus provided with such head, and a method for manufacturing liquid discharge heads as well.
In order to achieve the objects described above, an ink jet head of the present invention comprises a head substrate provided with a plurality of ink paths, and at the same time, each of the pressure generating devices being arranged for each of the paths; and an orifice plate provided with ink discharge openings each communicated with each of the ink paths. Then, the bonding surface side of the orifice plate to the substrate is provided at least with the surface treatment.
The orifice plate is resin containing fluorine.
The surface treatment provided for the fluororesin is plasma process, and fluororesin is coated on the bonding surface of the substrate to the orifice plate, and then, the plasma treatment is also given to the bonding surface of the substrate, hence bonding the orifice plate to the substrate by the self-bond thereof.
The surface treatment provided for the fluororesin is laser irradiation, and laser is also irradiated to the bonding surface of the substrate to the orifice plate, and then, the bonding surface of the orifice plate to substrate is activated and bonded.
The surface layer of the fluororesin is modified by the surface treatment for the provision of conductivity, and a metal plating process is performed for the conductive layer to be bonded to the substrate using a bonding agent.
Also, in order to achieve the object described above, the method for manufacturing ink jet heads of the present invention comprises the steps of preparing a head substrate provided with a plurality of ink paths and pressure generating devices each arranged for each of the paths; preparing an orifice plate provided with ink discharge openings communicated with each of the ink paths and bonded to the head substrate; performing the surface treatment on the bonding surface side of the orifice plate to the substrate; and bonding the orifice plate and the head substrate.
The orifice plate is resin containing fluorine, and plasma process is provided for the fluororesin, at the same time, coating fluororesin on the bonding surface of the substrate to the orifice plate, with the plasma treatment being also provided for the bonding surface of the substrate to enable the orifice plate and substrate to be bonded by the self-bond.
The orifice plate is resin containing fluorine, and Ar laser is irradiated to the fluororesin, and at the same time, the Ar laser being irradiated to the bonding surface of the substrate to the orifice plate to activate the bonding surface of the orifice plate to substrate for bonding.
The orifice plate is resin containing fluorine, and the surface layer of the fluororesin is modified for the provision of conductivity, and a metal plating process is performed for the conductive layer to be bonded to the substrate using a bonding agent.
Also, in order to achieve the objects described above, the liquid discharge head of the present invention comprises a head substrate provided with a plurality of discharge energy generating elements for generating thermal energy to create bubbles in liquid, and a plurality of liquid flow paths having the discharge energy generating elements arranged therefor; and an orifice plate formed by material having ink repellency, and provided with a plurality of ink discharge ports each communicated with each of the ink flow paths, at the same time, being bonded to the head substrate. Then, the orifice plate is bonded to the head substrate by the self-bond thereof.
In accordance with the invention described above, two substances are bonded by the molecular chains which are diffused each other when the head substrate and the orifice plate are bonded together. With the orifice plate being bonded by the so-called self-bond thereof, it becomes possible to secure the bonding force between the orifice plate having ink repellency and the head substrate even when fluororesin or the like which has ink repellency is used as the material of the orifice plate, for example. Also, by use of such orifice plate that has ink repellency, it becomes possible to obtain a liquid discharge head which is capable of stabilizing the discharge direction of ink discharged from the discharge ports formed on the orifice plate, at the same time, maintaining a good ink repellency for a long time. Further, since the orifice plate is bonded to the head substrate by the self-bond thereof assuredly, it becomes possible to reduce the influence that may be exerted by the thermal expansion of each of the structural parts of the liquid discharge head due to heat generated by the discharge energy generating elements when driving the liquid discharge head, hence obtaining the liquid discharge head whose discharge characteristics are stabilized.
It is preferable to use fluororesin as the material of the orifice plate. With the fluororesin used as the material of the orifice plate, it becomes possible to provide the orifice plate with ink repellency so as to stabilize the discharge direction of ink discharged from the discharge ports of the orifice plate.
Also, the liquid discharge head may be structured with an elemental substrate having a plurality of the discharge energy generating elements on the surface thereof, and a ceiling plate having a plurality of grooves constituting each of the liquid flow paths, and bonded to the surface of the elemental substrate.
Further, there may be provided a plurality of movable members arranged on the elemental substrate to face each of the discharge energy generating elements, and one end of them is fixed on the upstream side of the advancing direction of liquid in the each of liquid flow paths, and the other end thereof is made free.
It is also preferable to form the recessed portions on the bonding surface of the head substrate to the orifice plate, and the extrusions on the orifice plate in the state of being fitted into the recessed portions when the orifice plate is bonded to the head substrate.
It is also preferable to form the recessed portions on bonding surface of the head substrate to the orifice plate, and with the extrusions fitted into the recessed portions being formed on the orifice plate, it becomes possible to position the orifice plate by fitting the recessed portions and the extrusions when the orifice plate is bonded to the head substrate.
It is preferable to form the extrusions of the orifice plate and the discharge ports by the etching process using high-luminance X rays.
Also, the head cartridge of the present invention comprises a liquid discharge head, and a liquid container holding liquid to be supplied to the liquid discharge head.
In accordance with the present invention, since the head cartridge is provided with the above-described liquid discharge head, it is possible to obtain a highly reliable head cartridge.
Further, the liquid discharge recording apparatus of the present invention comprises the above-described liquid discharge head, and a recording medium supplying device for carrying a recording medium receiving liquid discharged from the liquid discharge head.
In accordance with the present invention, it is possible to obtain the liquid discharge recording apparatus capable of recording in good condition for a long time, because as described above, the apparatus is provided with the liquid discharge head whose orifice plate can maintain the good ink repellency for a long time, and at the same time, the bonding force between the orifice plate and the head substrate is assuredly secured. Also, the liquid discharge recording apparatus thus obtained is capable of recording on a recording medium stably against the temperature changes or the like.
Further, the method for manufacturing liquid discharge heads of the present invention comprises the steps of bonding an orifice plate formed by material having ink repellency, and provided with a plurality of ink discharge ports each communicated with each of the ink flow paths to a head substrate provided with a plurality of discharge energy generating elements for generating thermal energy to create bubbles in liquid, and the liquid flow paths having the discharge energy generating elements arranged therefor. With this method, the orifice plate is bonded to the head substrate by the self-bond thereof.
In accordance with the present invention, the orifice plate is bonded to the head substrate by the self-bond thereof. Therefore, as described earlier, when fluororesin or the like is used as the material of the orifice plate, it is possible to bond assuredly the orifice plate having ink repellency to the head substrate. Also, it is possible to reliably bond the orifice plate to the circumferential portions of the liquid flow paths on the bonding surface of the head substrate to the orifice plate. Therefore, at the same time that the orifice plate can maintain a good ink repellency for a long time, it becomes possible to reduce the influence that may be exerted by the thermal expansion of each of the structural parts of the liquid discharge head due to heat generated by the discharge energy generating elements when driving the liquid discharge head, hence obtaining the liquid discharge head whose discharge characteristics are stabilized.
For the above-described method for manufacturing liquid discharge heads, it is preferable to use fluororesin as the material of the orifice plate. With the fluororesin used as the material of the orifice plate, it becomes possible to manufacture the liquid discharge head capable of stabilizing the discharge direction of ink discharged from the discharge ports formed on the orifice plate, and at the same time, the orifice plate of which is able to maintain a good ink repellency for a long time.
More precisely, this method for manufacturing liquid discharge heads comprises the steps of transferring or coating fluororesin to the bonding surface of the head substrate to the orifice plate; performing the graft polymerization on the bonding surface of the head substrate having the fluororesin transferred or coated thereon, and the bonding surface of the orifice plate to the head substrate; and heating the bonding surface of the head substrate having the fluororesin transferred or coated thereon, and the bonding surface of the orifice plate to the head substrate, and bonding under pressure the bonding surfaces of the head substrate and the orifice plate themselves.
Further, it is preferable to form recessed portions on the bonding surface of the head substrate to the orifice plate, and extrusions on the orifice plate to be fitted into the recessed portions in the state of the head substrate being bonded to the orifice plate; and positioning the head substrate and the orifice plate by fitting the recessed portions and the extrusions together when the head substrate is bonded to the orifice plate. Here, it is also preferable that before the step of bonding the head substrate and the orifice plate by the self-bond thereof, the extrusions and the discharge ports on the orifice plate are formed by etching process using high-luminance X rays.
As described above, when the orifice plate is bonded to the head substrate, the extrusion formed on the orifice plate is fitted into the recessed portion formed on the bonding surface of the head substrate to the orifice plate for positioning the head substrate and the orifice plate. As a result, there is no need for a complicated apparatus that performs image process or the like for such positioning operation, and the liquid discharge head can be manufactured by use of a simpler apparatus. Also, with the formation of the extrusions and the discharge ports on the orifice plate by the etching process using the high-luminance X rays before the head substrate is bonded to the orifice plate, it is possible to form the discharge ports on the orifice plate in high precision and high density, because the mask adopted for the etching process is produced by the photolithographic process. As a result, it becomes possible to form the extrusions and the discharge ports in high precision and high density.
Further, in order to achieve the above-described objects, the liquid discharge head of the present invention comprises a head substrate provided with a plurality of discharge energy generating elements for generating thermal energy to create bubbles in liquid, and a plurality of liquid flow paths having the discharge energy generating elements arranged therefor; and an orifice plate formed by material having ink repellency, and provided with a plurality of ink discharge ports each communicated with each of the ink flow paths, at the same time, being bonded to the head substrate. For this liquid discharge head, the orifice plate is provided with the plate member having ink repellency, at the same time, the discharge ports being formed thereon, and an reinforcement member for reinforcing the plate member.
In accordance with the invention described above, the orifice plate is provided with the plate member having ink repellency and the reinforcement member that reinforces the plate member. As a result, even if a thin resin material is used for the plate member, for example, the strength of the orifice plate has been enhanced to make it possible to prevent the plate member from being deformed due to head when the orifice plate is bonded to the head substrate by a high-temperature process. With the prevention of the deformation of the plate member where the discharge ports are formed, it becomes possible to bond the orifice plate to the head substrate assuredly by a high-temperature process without spoiling the discharge characteristics, and at the same time, it is possible to obtain a highly reliable liquid discharge head which is sufficiently capable of coping with the environmental changes due to heat or the like. Also, when the orifice plate is provided with such plate member having ink repellency, the discharge direction of ink, which is discharged from the discharge ports formed on the plate member, is stabilized to make it possible to obtain the liquid discharge head whose orifice plate is capable of maintaining a good ink repellency for a long time.
It is also preferable to form recessed portions on the bonding surface of the head substrate to the orifice plate, and the extrusions fitting into the recessed portions on the orifice plate for positioning the head substrate and the orifice plate.
As described above, with the formation of the recessed portions on the bonding surface of the head substrate to the orifice plate, and also, the formation of the extrusions on the orifice plate to fit into such recessed portions, it becomes possible to position the orifice plate by fitting the extrusions into the recessed portions when the orifice plate is bonded to the head substrate.
More precisely, it is preferable that the reinforcement member is a metal layer formed on one surface of the plate member, and the orifice plate is provided with the double layer structure formed by the layer of the plate member having ink repellency, and the metal layer.
Also, it is preferable that fluororesin or the like is used as the material of the plate member, and that the discharge ports on the orifice plate are formed by the etching process using high-luminance X rays.
Also, it may be possible to structure with the head substrate comprising the elemental substrate having a plurality of discharge energy generating elements provided for the surface thereof, and a ceiling plate having a plurality of grooves constituting each of the liquid flow paths thereon, and bonded to the surface of the elemental substrate.
Further, the liquid discharge head may be able to further comprise a plurality of movable members arranged on the elemental substrate to face the discharge energy generating elements, respectively, at the same time, one end of each of them being fixed on the upstream side in the advancing direction of liquid in the liquid flow path, and the other end thereof is made free.
Also, the head cartridge of the present invention comprises the abode-described liquid discharge head, and a liquid container for holding liquid to be supplied to the liquid discharge head.
In accordance with the present invention, since the head cartridge is provided with the liquid discharge head described earlier, it is possible to sufficiently cope with the environmental changes due to heat or the like, and to obtain a highly reliable head cartridge whose discharge characteristics are stabilized.
Furthermore, the liquid discharge recording apparatus of the present invention comprises the above-described liquid discharge head, and a recording medium supply device for carrying the recording medium for receiving liquid discharged from the liquid discharge head.
Also, the method for manufacturing liquid discharge heads of the present invention comprises the step of bonding an orifice plate provided with a plurality of discharge ports communicated with the liquid flow paths, respectively, to a head substrate provided with a plurality of discharge energy generating elements to generate thermal energy for the creation of bubbles in liquid, and the liquid flow paths having the discharge energy generating elements, respectively.
This method further comprises the steps of preparing a plate member having ink repellency for the manufacture of the orifice plate; forming an reinforcement member on the surface of the plate member having ink repellency for reinforcing the plate member; and manufacturing the orifice plate having the plate member and the reinforcement member provided therefor.
In accordance with the invention described above, the orifice plate is provided with the plate member having ink repellency and the reinforcement member that reinforces the plate member. As described earlier, therefore, even if a thin resin material is used for the plate member, for example, the strength of the orifice plate has been enhanced to make it possible to prevent the plate member from being deformed due to head by use of the reinforcement member when the orifice plate is bonded to the head substrate by a high-temperature process. Therefore, it becomes possible to manufacture a highly reliable liquid discharge head without spoiling the discharge characteristics. Also, it is possible to manufacture a liquid discharge head whose orifice plate can maintain a good ink repellency for a long time, and whose discharge characteristics are stabilized at the same time, with the reduction of the influence that may be exerted by thermal expansion of each of the structural parts of the liquid discharge head due to head of the discharge energy generating elements when driving them.
More precisely, the method for manufacturing liquid discharge heads further comprises the steps of modifying the surface layer of the plate member to be the layer having conductivity for the formation of the reinforcement member on the surface of the plate member; and forming the reinforcement member on the surface of the plate member using a plating method with the surface layer of the plate member as the cathode.
As described above, with the formation of the reinforcement member formed by the plating method, it becomes easier to handle the reinforcement member of several tens of xcexcm thick, and the temperature resistance of the orifice plate is enhanced against the heat treatment. Also, the orifice plate having the reinforcement member with it can be manufactured by use of a simpler apparatus.
It is preferable to use fluororesin as the material of the plate member. In this way, the circumferential portions of the discharge ports on the orifice plate are provided with ink repellency, to stabilize the discharge direction of ink discharged from the discharge parts on the orifice plate, and the same time, it becomes possible to manufacture the liquid discharge head whose orifice plate can maintain a good ink repellency for a long time.
Further, it is preferable to form the recessed portions on the bonding surface of the head substrate to the orifice plate, and the extrusions on the orifice plate in the state of being fitted into the recessed portions when the orifice plate is bonded to the head substrate, thus positioning the head substrate and the orifice plate by fitting the extrusions and recessed portion when the orifice plate is bonded to the head substrate. Here, it is preferable to form the extrusions of the orifice plate and the discharge ports by the etching process using high-luminance X rays.
As described above, when the orifice plate is bonded to the head substrate, the extrusions formed on the orifice plate are fitted into the recessed portions formed on the substrate, thus positioned the head substrate and the orifice. As a result, there is no need for the use of any complicated apparatus that performs image process or the like for positioning. With a simpler apparatus, the positioning is possible. Also, the discharge ports on the orifice plate are formed by etching process using high-luminance X rays, and the mask used for such etching is produced by the lithographic process. Therefore, it becomes possible to form the discharge ports in high precision and high density.